Milwaukee, Wis.: one of Milwaukee's water treatment plants became contaminated with cryptosporidium and killed more than 100; 403,000 cases reported.

2009

in April, H1N1, also known as Swine Flu, breaks out and quickly spreads to more than 70 countries. The Centers for Disease Control reports that between April and October, 22 million Americans had contracted the virus, 98,000 required hospitalization, and about 3,900 people died from H1N1-related causes.

2010

California: an outbreak of whopping cough causes the death of ten infants; 9,477 cases reported.